Active Caster-Based Holonomic Mobile Platform for Improving C-Arm Mobility and Usability

Abstract

The C-arm, a critical device in minimally invasive surgery, captures X-ray images during operations. Positioning and orienting the C-arm, which is typically heavy, is challenging when making precise adjustments. Its nonholonomic wheel structure restricts immediate motion in any direction, complicating user control. Maneuvering the C-arm with a steering lever and pushing and pulling are inconvenient and provide imprecise movement control. This adjustment method necessitates repetitive repositioning and additional X-ray imaging, leading to delays in surgery and increased radiation exposure. This study presents a holonomic mobile platform that utilizes active casters to move a C-arm easily and accurately. This is a novel approach that has not been explored in any other study. The proposed mobile platform can automatically return a C-arm accurately to a predetermined position and orientation. In addition, a power-assisted hand-guiding function was implemented, enabling intuitive and convenient operation of the heavy C-arm and making it feel light to the user while handling and moving. The design process of the prototype is presented, and its performance is verified through experiments. In the experimental evaluations for automatic repositioning, the linear position error during automatic repositioning was found to be an average of 0.05 mm, with an orientation error of $0.0036^{\circ }$. The standard deviations for these errors were 0.02 mm and $0.0028^{\circ }$, respectively, demonstrating high reproducibility and performance.